Microencapsulated ant bait

Abstract

A method of manufacture and the product made thereby are set forth; in the preferred and illustrated embodiment, a core including an insect poison is encapsulated by shell material melting and hardening for encapsulation. The core is primarily soybean extract mixed with DURSBAN TM insecticide, an example of a toxicant. The surrounding shell or encapsulation is formed by melt extrusion of shell material. The surrounding shell encloses the core material to form an impervious shell. The surrounding shell includes soy protein as an insect attractant mixed in gelatin or poly(vinyl alcohol). A gelling agent such as carrageenan and the attractant were added to the shell. The beads formed by the melt extrusion encapsulation has sufficient shell strength to enable mechanical handling for dispensing, are resistant to water, do not bleed from the inside to the outside, and yet can be penetrated by the insect.

What is claimed is: 
     
       1. A solid insecticidal bait comprising a generally spherical pellet of approximately 300 or more microns diameter having an enclosed core primarily made of a target insect attractant food, and mixed therein an insect toxicant in sufficient quantity for effective eradication, and including a surrounding polymeric water resistant shell impervious to the attractant food, said shell formed of poly(vinyl alcohol) or type B gelatin mixed with an attractant protein and gelling agent and wherein the core is up to about 70% by weight of the bait. 
     
     
       2. The bait of claim 1 wherein said shell includes about 4% soybean protein, about 6% carrageenan, and about 90% of either poly(vinyl alcohol) or type B gelatin. 
     
     
       3. The bait of claim 1 including a surfactant added in trace quantity to said core. 
     
     
       4. The bait of claim 1 wherein the toxicant is an ingestion poison. 
     
     
       5. The bait of claim 1 wherein the toxicant is up to about 2% by weight of said core. 
     
     
       6. The bait of claim 5 wherein the remainder of said core is edible soybean oil. 
     
     
       7. The bait of claim 5 wherein the bait includes up to about 2% by weight an ingestion poison and the remainder of said core is soybean oil, and said shell includes up to about 5% of soybean protein in a quantity sufficient to attract the target insect. 
     
     
       8. The bait of claim 7 wherein said shell includes about 4% soybean protein, about 6-7% carrageenan, and about 89-90% of either poly(vinyl alcohol) or type B gelatin. 
     
     
       9. The bait of claim 1 wherein the toxicant is oil soluble. 
     
     
       10. The bait of claim 1 wherein said food is primarily soybean oil. 
     
     
       11. The bait of claim 1 wherein the toxicant is chlorpyrifos.